Leave-in-Place Concrete Formwork Combining Plate Dowels, Divider Plates, and/or Finishing, Armoring and/or Sealing Molding

ABSTRACT

A leave-in-place forming system is for concrete slabs and pavements. It comprises a number of components that can include two or more of the following but is not limited to two or more of the following: a plate dowel for load transfer between adjacent concrete panels (joint stability), a divider plate (which could be sheet metal, plastic or other rigid material), and an assembly or molding to finish the concrete to, that armors the joint and/or provides a water-tight seal to the joint. The joint assembly could incorporate an integral setting assembly or bracket, or could be used with a re-usable setting bracket. The integral assembly or bracket is most suitable when it is desirable to place concrete to both sides of the joint assembly at the same time. The re-usable setting bracket is most suitable where concrete is placed to just one side of the assembly and it is desirable to re-use the setting assembly.

This application claims priority to U.S. Provisional Application Ser.No. 61/673,061, filed Jul. 18, 2012.

TECHNICAL FIELD

This invention relates to concrete flatwork such as slabs and pavements,joints for such flatwork, and products for providing improved concreteflatwork joint performance.

BACKGROUND OF THE INVENTION

There are generally four types of joints used in concrete flatwork(slabs and pavements): isolation joints, expansion joints, constructionjoints and contraction joints. Isolation joints are used to create aseparation between the concrete flatwork panel and adjacent panels orother building components, such as walls, columns, trenches, man-holes,bollards, etc. Expansion joints are used in the same way as an isolationjoint except that it contains a compressible material or void spacesufficient to accommodate subsequent expansion of the concrete flatworkpanel(s). Construction joints are used at the termination of a singleslab placement and thus defines the joint between adjacent panels castindependently. Construction joints are generally formed with removableor leave in place forms, sawcut full depth, or slip formed (temporaryforms used with low slump concrete mixtures). Contraction joints areused as means of allowing for the concrete contraction by providing aplane of weakness. Contraction joints are often induced cracks createdwith the use of a saw cut, crack inducer, or tooled notch in the surfaceof the concrete.

Each joint type has its drawbacks and problems. Isolation joints oftendo not provide for positive load transfer between adjacent panels andother building components. Expansion joints are wider than other jointsand therefore more prone to both joint spalling, such as damage to thejoint edges, from wheeled traffic or other objects crossing andimpacting the joint, and the intrusion of liquids. The intrusion ofliquids can cause numerous problems including the pumping of saturatedsubgrade materials and faulting of pavement panels in exteriorpavements, and subgrades heaving due to frost in cold climates or areaswhere expansive soils are found. Construction joints can also be proneto joint spalling under traffic especially if sufficient load transferis not provided to create sufficient joint stability. Contraction jointsare prone to dominant joint activation where some joints open wider thanothers, leading to the loss of load transfer through aggregate interlockthus also increasing the likelihood of joint spalling. There areadditional issues as well.

All four joint types are generally filled or sealed after theirconstruction in an attempt to either protect the joint from spallingunder traffic or prevent the ingress of moisture, liquids, contaminants,or bacteria. Load transfer with joint stability is most often providedin any of these joints through the use of either dowels, which aregenerally steel bars that are round or square in section, or keyways,which are tongue and groove type joints which can be formed withremovable or leave in place forms.

There are products on the market that provide improved jointperformance. Concerning load transfer, plate dowels are described inU.S. Pat. Nos. 6,354,760 and 7,481,031, the disclosures of which areincorporated by reference in their entireties. Concerning joint sealing,an assembly designed to seal joints during the construction stage andnot afterwards is described in Patent Co-operation Treaty documentnumber PCT/AU2009/001376, the disclosure of which is incorporated byreference in its entirety.

SUMMARY OF THE INVENTION

Products have not previously existed that have all the advantages ofboth load transfer and joint sealing according to the products of thecited and incorporated patent and document as opposed to the separateload transfer and joint sealing advantages of the separate products inthe cited and incorporated patent and document. The envisioned productshave never existed in an assembly for simplified use of the contractor.The invention, which includes both products and methods, combines aplate dowel and either an armored joint assembly or a joint sealingassembly with a leave-in-place and/or reusable formwork assembly. Unlikeany other joint product or system it is envisioned to be used in placeof any one of the four joint types described above and overcome thevarious drawbacks of them listed above. By providing the jointstability, joint protection (armoring) and/or joint sealing required ina single assembly with a leave-in-place and/or reusable form, theinvention provides the opportunity for the contractor to place multiplepanels at one time and negate the need for subsequent processes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section through two slabs of concrete on a subgradeexposing in cross-section an embodiment of the joint assembly accordingto the invention.

FIG. 2 is a detailed view of a portion of FIG. 1.

FIG. 3 is a set of perspective views of exemplary load transfer platesof the type of plate dowel 62 in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

As in FIG. 1, two slabs of concrete 2 and 4 are seen in cross-sectionwhen cut open or seen from their outer edges. The concrete has the usualconstruction of binder and inclusions such as aggregate 6. The slabs 2,4 rest on a typical subgrade or base material 8.

A divider plate 10 defines the upright edges 12, 14 of the slabs 2, 4 ata joint 16 where the slabs are adjacent each other. They “meet” at thejoint 16 in the sense that they terminate at the joint 16. They are also“separated” at the joint 16 in the sense that the divider plate 10 liesbetween them. They also further separate if the joint 16 between them isa construction and/or contraction joint and they move back from eachother, under the action of concrete shrinkage or otherwise.

The divider plate 10 includes a vertically oriented extension 18, whichextends from the subgrade or base 8 to the top of the slabs 2, 4. Theextension 18 may have this extent by reason of incorporating a settingbracket 20 and a finishing and/or armoring structure 22 at set distancesfrom each other equal to the desired heights of the slabs 2, 4, or bethe same heights with exclusion of one or more of the setting bracket 20and finishing strip 22, or be other extents relative to the slabs 2, 4such as an extent shortened for saw cutting of the top portion of thejoint 16.

As just expressed, the divider plate 10 as shown in FIG. 1 includes aplate support such as a setting bracket 20 and a top structure such as afinishing structure 22. The setting bracket 20 includes a planarhorizontal portion for resting and/or fastening to the subgrade or base8, or the plate support may include features similar to the bracket 20which equivalently provide adequately for resting and/or fastening tothe subgrade or base 8 and supporting the divider plate 10. Equivalentsmight, for example, include wires that project feet to the subgrade orbase 8. They might include stakes driven into the subgrade or base 8 towhich the plate support may attach. The setting bracket 20 also may becontinuous along the joint 16 or intermittently project to the subgradeor base 8. The divider plate 10 may be metal, such as aluminum, or othermaterials as desired, such as plastic.

Again as just expressed, and as shown in larger size in FIG. 2, thedivider plate includes a top structure such as a finishing and armoringstructure 22. The extreme top surfaces 21, 23 of the structure 22 aresubstantially equal in height and provide guides for concrete surfacefinishing tools and equipment such as screeds, so as to permit accurateleveling, for example, of the tops of the slabs 2, 4.

The structure 22 as in FIG. 2 and some embodiments of invention alsoinclude(s) joint expansion and contraction elements such as co-operatingrails 24, 26, upon which the top surfaces 21, 23 are formed. Theseelements are movable with their slabs as the slabs expand and/orcontract, with the top surfaces 21, 23 moving closer together andfarther apart as dictated by expansion and contraction.

Rails of the top structure may take various specific forms, as forexample the rails 24, 26 take the form of substantially mirror-imagecomponents of greater height that width, and upper and lower elements28, 30 and 32, 34 that extend toward each other in close vertical andhorizontal association. The upper elements 32, 34 constitute as mostpreferred an overlapping pair of elements that by the turns of theminimal space between them create a short “labyrinth” of overlap andeffectively “close” the space below themselves by their overlap.

The rails of a top structure may as in rails 24, 26, also have laterallyextending segments 36, 38, 40, 42 that increase the thicknesses ofportions of their upright elements 44, 46 and provide channels such as51, 53, 55, 57 for seal elements such as 52, 54, 56, 58, such ashydrophilic gaskets of suitable rubber and the like. Additional channelsand seal elements such as channel 59 and seal element 60 may also beincluded, in the case of 59, 60, for example, under upper element 32 ofrail 24.

Retaining elements such as spring retaining elements 48, 49 may existwithin the interiors of the rails such as rails 24, 26, or equivalentstructures for fitting against the portion 50 of the divider plate 10 inthe area of the top structure such as structure 22. The rails 24, 26 maybe releasably fastened together at various locations to rest atopportion 50 during slab formation, or provided with structure thatequivalently places rails 24, 26 in association with portion 50 duringslab formation, such as clips and the like. The fastening elementsshould release the rails 24, 26 from each other and may release therails 24, 26 from the portion 50 upon the appropriate degree ofhardening of the slabs 24, 26.

The rails 24, 26 and all structures shown in FIG. 2 may be extended inlongitudinal dimension (into the paper of FIG. 2) and be continuousextrusions or be intermittent in longitudinal extent, or otherwise, asfor example, at various extents beyond their length exchanging orvarying locations or sizes of specific structures. As most preferred,the rails and structures are continuous extrusions for manufacturingsimplicity.

Referring again to FIG. 1, the preferred embodiment may also include andmost desirably does include load transfer plates such as for exampleplate dowel 62. As in the perspective views of FIG. 3, the plates maytake on a variety of shapes, including oval 63, rectangular 65,alternating triangular 67, 69 and double triangular 71. Load platesupports such as load plate support bracket 73 in FIG. 1 are attached toand/or formed with or from divider plate 10. The load plate supportssupport load plates relative to divider plate 10 and assure or at leastassist assuring proper orientations of load support plates for best useof the load plates.

In use, as by now perceived, to form a joint and pour two adjacent slabssimultaneously, the subgrade or base is prepared, as in FIG. 1, dividerplates are extended and secured in series along the intended jointlocation for the distance the joint is to cover (or more or less), as inFIG. 1, load plates are installed on their supports, as in FIG. 1, topstructures are installed, as in FIG. 1, and concrete slabs are poured.The stated steps are carried out in such orders as make sense, with someinterchangeability of order, such as placing load plates last beforepouring, installing top structures last before pouring, etc. To theextent appropriate, additional steps are also taken such as preparingthe load plates to break from being locked into poured concrete at bothends, and the like. Concrete finishing using the top surfaces of the topstructure may or may not occur, and indeed, more or less than all thestructures shown may be included or excluded from the method, as forexample, the top structures, which may or may not be included in somesituations, if and where saw cutting to create joints is desired.

The invention and especially its preferred embodiment are now describedin such full, clear and concise and exact manner as to enable a personof ordinary skill in the art to make and use the same. All embodimentsof invention that come with the scope of claims to be appended on thepreparation and filing of a non-provisional patent application are to bedeemed to be covered by the claims.

What is claimed is:
 1. A concrete flatwork joint product for theadvantages of both load transfer and joint sealing in an assembly forsimplified use of a contractor, comprising: a plate dowel; at least oneamong the group comprising an armored joint assembly and a joint sealingassembly; and at least one among the group comprising a leave-in-placeformwork assembly and a reusable formwork assembly; whereby the productis useful in isolation joints, expansion joints, construction joints andcontraction joints, provides the joint stability, jointprotection/armoring and/or joint sealing required in a single assemblywith a leave-in-place and/or reusable form, tends to overcome thedrawbacks of isolation joints that do not provide for positive loadtransfer between adjacent panels and other building components,expansion joints that are prone to both joint spalling, such as damageto the joint edges, from wheeled traffic or other objects crossing andimpacting the joint, and the intrusion of liquids, construction jointsthat are prone to joint spalling under traffic, and contraction jointsthat are prone to dominant joint activation, leading to the loss of loadtransfer through aggregate interlock, and provides the opportunity forthe contractor to place multiple panels at one time and negate the needfor subsequent processes.
 2. A concrete flatwork joint product as inclaim 1, in which a divider plate defines the upright edges of slabs ata joint where the slabs are adjacent each other.
 3. A concrete flatworkjoint product as in claim 2 in which the divider plate includes avertically oriented extension, which extends from the subgrade or baseto the top of the slabs.
 4. A concrete flatwork joint product as inclaim 3 in which the extension incorporates a setting bracket and atleast one among the group of a finishing structure and an armoringstructure.
 5. A concrete flatwork joint product as in claim 2 in whichthe divider plate includes a vertically oriented extension, whichextends from the subgrade or base to below the top of the slabs, for sawcutting of a top portion of the joint.
 6. A concrete flatwork jointproduct as in claim 2 in which the divider plate includes a platesupport and a top structure.
 7. A concrete flatwork joint product as inclaim 6 in which the plate support includes a setting bracket.
 8. Aconcrete flatwork joint product as in claim 6 in which the top structureincludes a finishing structure.
 9. A concrete flatwork joint product asin claim 8 in which the finishing structure has extreme top surfaceswhich are substantially equal in height to each other and provide guidesfor concrete surface finishing tools and equipment such as screeds, soas to permit accurate leveling, for example, of the tops of the slabs.10. A concrete flatwork joint product as in claim 9 in which thefinishing structure includes joint expansion and contraction elementsthat are movable with their slabs as the slabs expand and/or contract,with the top surfaces moving closer together and farther apart asdictated by expansion and contraction.
 11. A concrete flatwork jointproduct as in claim 6 in which the top structure includes rails in theform of substantially mirror-image components of greater height thatwidth, and upper and lower elements that extend toward each other inclose vertical and horizontal association.
 12. A concrete flatwork jointproduct as in claim 11 in which the upper elements constitute anoverlapping pair of elements that by turns of minimal space between themcreate a labyrinth of overlap and effectively close the space belowthemselves by their overlap.
 13. A concrete flatwork joint product as inclaim 11 in which the rails of the top structure have laterallyextending segments that increase the thicknesses of portions of theirupright elements and provide channels for seal elements such ashydrophilic gaskets of suitable rubber and the like.
 14. A concreteflatwork joint product as in claim 13 in which retaining elements existwithin the interiors of the rails for fitting against a portion of thedivider plate in the area of the top structure
 15. A concrete flatworkjoint product as in claim 14 in which the rails are releasably fastenedtogether at various locations to rest atop the portion of the dividerplate during slab formation.
 16. A concrete flatwork joint product as inclaim 14 in which the rails are provided with fastening elements thatplace the rails in association with the portion of the divider plateduring slab formation, the fastening elements releasing the rails fromeach other and releasing the rails from the portion of the divider plateupon the appropriate degree of hardening of the slabs.
 17. A concreteflatwork joint product as in claim 1 in which the load plates includeload transfer plates in the form of plate dowels which take on a shapefrom among the group including oval, rectangular, alternating triangularand double triangular.
 18. A method of forming a joint and pouring twoadjacent slabs simultaneously, comprising, in variable order: preparingone among the group comprising a subgrade and a base; extending andsecuring divider plates in series along intended joint locations for thedistances the intended joints are to cover, the divider plates includingload plate supports; installing load plates on the load plate supports;doing at least one among the group of installing top structures orsawcutting the intended joints; and pouring concrete slabs.
 19. Themethod of claim 18 wherein the placing of load plates occurs last beforepouring as among the installing of load plates and the installing of topstructures.
 20. The method of claim 18 further comprising preparing theload plates to break from being locked into poured concrete.
 21. Themethod of claim 18 in which top structures are installed.
 22. The methodof claim 18 comprising finishing concrete using top surfaces of the topstructure.